Created by ImPat on September 26, 2017
Step 1: Peel and thinly slice all of the onion into half moons and transfer all the onions to the slow cooker/crock Pot (4 - 6 quart size) and it should be half to three-quarters full.
Step 2: Drizzle the olive oil or melted butter and then add the salt over the top of the onions and toss to evenly coat all the onions with a thin glaze of oil or melted butter.
Step 3: Cover the slow cooker/crock pot and cook for 10 hours on low.
Step 4: If you are around while the onions are cooking, stir them occasionally as this will help them cook more evenly, but isn't strictly necessary.
Step 5: After 10 hours, the onions will be golden-brown and soft, and they will have released a lot of liquid, so if you like them as they are now, stop cooking and pack them up once they have cooled down.
Step 6: If you'd like jammier, more concentrated onions with a deeper colour, continue to cooking for another 3 to 5 hours on low and leave the lid ajar so the liquid can evaporate, check every hour and stop cooking whenever the onions look and taste good to you.
Step 7: Remove the onions with a slotted spoon and transfer them to refrigerator or freezer in containers.
Step 8: If any liquid remains in the slow cooker, crock pot, transfer the liquid to a separate container and this can be used as cooking broth in another recipe.
Step 9: Onions keep in the refrigerator for 1 week and in the freezer for at least 3 months.